1. Field of the Invention
The present invention relates to a magnetic tape cartridge in which a single tape reel with magnetic tape wound thereon is rotatably housed within a cartridge case.
2. Description of the Related Art
In magnetic tape cartridges, which are in general use as storage media that are employed in external storage units for computers, etc., there is known a type where a single tape reel with magnetic tape wound thereon is rotatably housed within a cartridge case. This magnetic tape is employed to archive data for computers, etc. As important information has been stored, the magnetic tape cartridge is constructed so that problems, such as tape jamming, etc., do not occur and that the magnetic tape is not pulled out of the cartridge case inadvertently.
The magnetic tape has a tape leader pin firmly attached to the leading end thereof. When this magnetic tape cartridge is loaded into a drive apparatus, a leader-pin holding member on the drive apparatus side engages the tape leader pin, pulls out the magnetic tape from the cartridge case, and loads the tape into the drive apparatus. On the other hand, when the magnetic tape cartridge is unloaded from the drive apparatus, the magnetic tape is rewound on the tape reel, and the tape leader pin is returned into the cartridge case by the leader-pin holding member. The cartridge case is formed by fastening upper and lower shells of synthetic resin together with a plurality of small screws. In the vicinity of an opening formed in the upper and lower shells of the cartridge case, the tape leader pin is detachably held at the upper and lower ends thereof by a leader-pin holding spring, etc.
As shown in FIG. 6, the cartridge case is also equipped with a side notch 21, which is formed in the side wall 3b of the lower shell 3. This side notch 21 is open near the front corner, in an insertion direction in which the cartridge case is inserted into the drive apparatus, of the side wall 3b approximately parallel to the insertion direction. The side notch 21 is surrounded by both the inside surface of the side wall 3b on the front side and the outside surface of a connecting rib 22 obliquely extending between the side walls 3b near the front corner.
FIG. 7 shows the state in which the magnetic cartridge is loaded into the drive apparatus. The drive apparatus is equipped with a bucket 40 formed by punching and bending a metal plate. If the magnetic cartridge is loaded into the drive apparatus, the bend portion 41a of the outer end of the locking claw 41 of the bucket 40 contacts elastically with the outer edge 21a of the side notch 21. In this way the magnetic tape cartridge is locked in a predetermined position.
However, since the outer edge 21a in the conventional magnetic tape cartridge is sharply formed, the locking claw 41 of the cartridge driver catches on the sharp edge, when the cartridge is taken out from the cartridge driver. Thus, the conventional cartridge becomes difficult to take out.
The portion of the side notch 21 that contacts with the locking claw 41 can be coated with Teflon™ (fluororesin) to reduce the sliding resistance. However, the Teflon™ coating cracks and peels off after prolonged use, and in that case, the locking claw 41 catches easily on the side notch 21.
In addition, as the construction shown in FIGS. 6 and 7 also has an inner edge 21c at the boundary of the side wall 3b and the front wall of the side notch 21, a locking claw catches on the inner edge 21c, depending on the shape of the locking claw.